Bag



y 5, 3947- H. VOLKSDORF 2,420,212

BAG

Filed April 1 1946 3 Sheets-Sheet 1 May 5, 19%? H. VOLKSDQRF BAG I s Sheets-Sheet 2 Filed April 1, 1946 y 1947. H. VOLKSDORF 2,429,212

BAG

Filed April 1, 1946 3 Sheets-Sheet 3 I m .Euzezzxy 262: mfis orf I Patented l Way 6, 1947 UNITED STATES PATENT OFFICE Hans Volksdorf, Philadelphia, Pa., assignor to Thomas M. Royal & 00., Philadelphia, Pa., a corporation of Pennsylvania Application April 1, 1946, Serial No. 658,759

12 Claims. (01. 22955) and bottom secured together by heat-sealing through the use of thermoplastic adhesive or sheet materials, such as Pliofilm and the like, is well known to the bag industry, and this method of securing togethe the seams and bottoms of bags has been and is employed extensively in the manufacture of bags having so-called fiat or square bottoms. Prior to the present invention, however, by reason of the intricate folds and construction embodied in so-called self-opening automatic and satchel type bag bottoms, it has not been possible effectively to manufacture bags having automatic, bottoms and satchel bottoms which are secured together by heat-sealing, and in those instances Where attempts have been made to provide bags having heat-sealed, automatic and satchel type bottoms such bags have proved defective in that they are not completely sift proof. Furthermore, such bottoms are not air-tight which is a desirable feature for packaging certain commodities.

With the foregoing in mind, the principal object of the present invention is to provide novel and improved bag constructions having bottoms of the so-called self-opening automatic type or satchel type which are completely heat-sealed.

Another object of the present invention is to provide a novel and improved bag of the bellowsfolded side wall type having a completely heatsealed self-opening or automatic bottom which is entirely proof against the leakage or sifting of any contents outwardly through the bottom, and which is completely air-tight.

Another object of the present invention is to provide a novel and improved bag having a comtion and manufacture thereof are hereinafter fully set forth and described with reference to the accompanying drawings, in which:

Fig. 1 is a view in. perspective of the outer sheet of a bag made according to the present invention.

Fig. 2 is a view similar to Fig.1 showing the outer sheet of the bag in association with an intermediate sheet of heat-sealable material.

Fig. 3 is a view similar to Fig. 2 showing the said outer and intermediate sheets of the bag in association with an inner or liner sheet.

Fig. 4 is a view in perspectiveof a tube formed from the triplex arrangement of sheets shown in Fig. 3.

Fig. 5 is an enlarged fragmentary perspective view showing one step in the formation of an automatic type bottom bag.

Figs. 6 and 7 are views similar to Fig. 5 showin additional steps in the formation of the automatic type bottom- Fig. 8 is a fragmentary perspective view showing the lower end portion of the finished bag with the automatic type bottom in opened relation.

Fig. 9 is a view in perspective of a flat tube embodying the triplex arrangement of sheets of the present invention fabricated preparatory to pro- Figs. 11 and 12 are views similar to Fig. 10 I showing additional steps. in the formation of the satchel type bag bottom; and

Fig. 13 is a fragmentary perspective view showing the finished bag with the satchel bottom in opened relation.

Referring now more particularly to the drawings, bags made according to the present invention comprise essentially an outer sheet I an intermediate sheet 2 and an inner or liner sheet 3. With reference more particularly to Figs. 1, 2 and 3 of the drawings, the outer sheet I has a top edge 4 and has its bottom edge portions cut away as shown to provide a tab portion 5 which projects beyond the inwardly offset bottom edge portion 6 and is predeterminedly spaced from and intermediate the parallel side edges 1 and 8 of the sheet. In line with the side edges of the tab 5, the sheet I is cut to provide slits 9 which extend inwardly from the bottom edge 6 of the said sheet perpendicular thereto.

Disposed upon the sheet I is the intermediate sheet 2 which is of a width corresponding to the sheet I but is arranged upon the latter so that 3 the side edges III and II of the sheet 2 are offset inwardly and outwardly, respectively, with respect to the side edges I and 8 of the sheet I. On the other hand, the sheet 2 in a direction lengthwise of the bag to be formed is such that the top edge I2 of said sheet 2 registers or coincides with the top edge 4 of the sheet I whereas the lower or bottom edge I3 of the sheet 2 extends or projects beyond the bottom edge 6 of the sheet I the same distance that the tab projects therefrom so that the bottom edge portions of the sheet 2 at opposite sides of the tab 5 are exposed and left uncovered by the outer sheet i.

The inner or liner sheet 3 is of the same size and configuration as the intermediate sheet 2 and associated therewith so that the side edges I4 and I5 of said sheet 3 are respectively offset inwardly and outwardly from the side edges I and II of the sheet 2, while the top and bottom edges I6 and I1, respectively, thereof are in register or coincide with the top and bottom edges I2 and I3 of the sheet 2. Formed in the bottom edge portion of the inner liner sheet 3 is a notch or recess I8 which is located centrally with respect to the tab of the outer sheet I so as to expose through the liner sheet 3 a portion or area IQ of the intermediate sheet 2. V

The outer sheet I and liner sheet3 may be of paper or other suitable flexible non-heat reactive material customarily employed in the manufacture of bags. However, the intermediate sheet 2 preferably is composed of heat-sealable or thermoplastic material, such as, for example,

Pliofllm, or' may be of Cellophane or other suitable sheet material having thereon a thermoplastic adhesive or other heat-scalable coating. In such circumstances, the several sheets I, 2 and 3 may be secured together in the relationship described to form a triplex structure merely by the application of heat to one or more selected zones of the associated sheets. When this has been done there is preferably applied along the top edge I8 of the liner sheet 3 a strip of thermoplastic adhesive 20 for use in closing the top of the bag when finished and filled with a selected commodity or article.

In one embodiment of the invention and to provide a bag of the bellows-folded side wall type having a self-opening or automatic type bottom, the triplex or laminated structure comprising the sheets I, 2 and 3 arranged as herein described, is folded into the tubular form shown in Fig. 4 with its opposite side portions tucked inwardly to provide reentrant bellows-' folded side walls 2I in accordance with conventional bag practice. In this form the respective side edge portions of the several sheets I, 2 and 3, offset as they are, overlap one another and are secured together in well-known manner such as by means of a suitable adhesive. More particularly, by reason of the offset relationship of the opposite side edges of the several sheets I, 2

and 3, when folded into the tubular form shown, the portion of the sheet I adjacent its side edge I overlies and is secured to the portion adjacent its other edge 8, and the portion of the sheet 2 adjacent its side edge III overlies and is se-- By reason of the cut-away bottom edge portions of the outer sheet I and the resulting explosur'e or projection of the intermediate sheet 2 beyond the bottom edge 6 of the outer sheet I to the extent of the tab 5 of the latter, it is to be noted. when the triplex or laminated structure of Fig. 3 is folded into the tubular form shown in Fig. 4, that the bottom edge portion of the sheet 2 is exposed extcriorly of the tube continuously about the bottom end thereof except for the area covered by the projecting tab 5 which is disposed centrally and transversely with respect to the under face of said tube. On the other hand, the inner or liner sheet 3 overlies the entire surface of the intermediate sheet 2 interiorly of the tube with the exception of the small area I9 exposed by the notch or recess I8.

The tube, with the side edges of the respective sheets thereof secured together as described to form a lengthwise seam, is provided with transverse creases 22 and 23 at predetermined spaced intervals located with reference to the bottom edge of the tube, and the bottom end portion of the tube is then folded to form a so-called automatic m self-opening bottom. This is accomplished according to conventional practice by first folding the upwardly facing portions of the bottom end of the tube along the crease 22 and simultaneously opening and distending the walls of said end portion so that they are disposed in a substantially vertical position. The side wall portions then are folded inwardly from opposite sides of the tube and laid flat upon the latter so that the bottom edges of the several sheets extend in a direction lengthwise of the tube as shown in Fig, 5 of the drawing thus forming op positely projecting substantially triangular flap sections 24 and 25, respectively, which are foldable upon the lines a and b produced by the crease 23 onto an intermediate rectangular bag bottom section 26.

With reference to Fig. 5, it is to be noted that with the bottom end portions of the bag tube folded as described, the bottom edge portions 2'! and 28 of the intermediate sheet 2 of heat-sealable material, which project beyond the bottom edge 6 of the outer sheet I, lie lengthwise of the bag tube for the full length of the bottom intermediate section 26 and flap sections 24 and 25 and are fully exposed so that when the flap portion 24 is folded along the line a upon the adjacent portion of the intermediate bottom'section 26, in the relation shown in Fig. 6 of the drawings, the exposed portions 21 and .28 of the section 26 will be in overlapping contact with one another with no portion of the outer paper sheet I interposed therebetween. Also, it is to be noted that when the flap portion 24 is folded as described and shown in Fig. 6, there remains exposed in the upper face of the flap a triangular area 29 of the intermediate heat-scalable sheet 2 at the apex of the said flap portion 24.

The other flap portion 25 is next folded alon the line b upon the adjacent portion of the intermediate bottom section 26 and the end of the flap portion 24, for example, in the relationship shown in Fig. 7 of the drawings, whereby the exposed portions 21, 28 and 29 of the sheet 2 in flap 25, section 25 and flap 24, respectively,

are disposed in direct contact with no intervening layer of paper. In addition, it is to be noted away portion in the liner sheet internally of the flap apex so that the folded thicknesses of the heat-scalable intermediate sheet 2 in that area are in direct contact with one another.

Consequently, when heat is applied to the bottom portions of the tube with the flap sections folded as described, the lapped and contacting portions 21 and 28 of the sheet 2 in the flap section 24 are heat-sealed to the underlying exposed portions 21 and 28 of the sheet 2 in the intermediate bag bottom section 26. Likewise, the

exposed portions 21 and 28 of the sheet 2 in' the flap section 25 are heat-sealed to the underlying exposed portions 21 and 28 f the sheet 2 in the bag bottom section 26 as well as to the underlying area 29 of the sheet 2 in the apex of the flap section 24. Furthermore, by reason l of the notch I8 in the liner sheet 3, the inner or outer layers or thicknesses of the sheet 2 at the apex of the flap 25 will be heat-sealed together thereby preventing all possibility of leakage or sifting of the bag contents outwardly through the bottom structure of the bag and providing a bottom structure for the bag that is completely air-tight. After the flap sections 24 and 25 have been heat-sealed together and to the respectively underlying areas of the portions 21 and 28 of the sheet 2 in the intermediate bag bottom section 26 as described, the tab 5 may be secured over and upon the folded flap sections 24 and 25 in the conventional manner, for example, by means of any suitable adhesive. In lieu of the procedure just described, it Will be obvious, of course, that the tab 5 may be provided with a coating of thermoplastic adhesive and secured in place by the application of heat independently of or at the same time that the flap sections 24 and 25 of the bottom structure are secured in folded relation upon the intermediate bag bottom section 26 as hereinbefore described.

In another embodiment of the invention and to provide a bag construction having a so-called satchel type bottom, the triplex or laminated structure comprising the sheets I, 2 and 3 arranged as herein described, is folded into the flat tubular form shown in Fig. 9 of the drawings with the offset edge portions of the several sheets overlapping one another and secured together in the manner set forth.

In this form, and as previously'described, by reason of the cut-away bottom edge portions of the outer sheet I and the resulting exposure or projection of the intermediate heat-scalable sheet 2 beyond the edge 6 of the outer sheet I, the bottom edge portion of the said sheet 2 is exposed exteriorly of the tube continuously about the bottom end thereof except for the area underlying the tab 5. On the other hand, the liner sheet 3 overlies the entire surface of the intermediate sheet 2 interiorly of the tube with the exception of the small area I 9a exposed by the notch or recess I8. The tube is transversely creased as at 22c...

With the side edges of the respective sheets secured together as described to provide a lengthwise seam, the bottom end portion of the flat tube of Fig. 9 is folded to form a so-called satchel type bottom. This is accomplished by first folding the upper face portion of the bottom end of the tube along the crease 22a thereby opening and distending the bottom end portions of the tube which are then folded inwardly from opposite sides of the tube flat upon the latter so that the bottom edges of the several sheets extend in a direction lengthwise of the tube as shown in Fig.

10 of the drawings, thus forming oppositely projecting substantially triangular flap sections 24a and 25a, respectively, which are foldable upon 5 the lines a and b onto an intermediate bag bottom section 26a.

With reference to Fig. 10, it is to be noted that with the bottom end portions of the bag'tube folded as described, the bottom edge portions 21a and 28a of the intermediate sheet 2 of heatsealable material, which project beyond the bottom edge 6 of the outer sheet I, lie lengthwise of the bag tube for the full length of the bottom intermediate section 26a and flap sections 24a and 25a and are fully exposed so that when the flap portion 24a is folded along the line a upon the adjacent portion of the intermediate bottom section 26a, in the relation shown in Fig. 11 of the drawings, the exposed portions 21a and 28a of the heat-sealable intermediate sheet 2 in flap 24a and section 26a will be in overlapping contact with one another with no portion of the outer paper sheet I interposed therebetween. Also, it is to be noted that when the flap portion 24a is folded as described and shown in Fig. 11, there remains exposed in the upper face of the flap a triangular area 29a of the intermediate heat-sealable sheet 2 at the apex of the said flap portion 24a.

The other flap portion 25a is next folded along the line b upon the adjacent portion of the intermediate bottom section 26a and the end of the flap portion 24a, for example, in the relationship shown in Fig. 12 of the drawings, whereby the exposed portions 21a, 28a and 29a of the sheet 2 in flap 25a, section 26a and flap 24a, respectively, are disposed in direct contact with no intervening layer of paper. In addition, it is to be noted that the notch or recess I8 provided in the inner or liner sheet 3 of the tube is located at the apex of the flap portion 25a and thus provides a cut-away portion in the liner sheet internally of the flap apex so that the folded thicknesses of the heat-scalable intermediate 45 sheet 2 in that area are in direct contact with one another.

Consequently, when heat is applied to the bottom portions of the tube with the flap sections folded as described, the lapped and contacting 50 portions 21a and 28a of the sheet 2 in the flap section 24a are heat-sealed to the underlying exposed portions 21a and 28a of the sheet 2 in the intermediate bag bottom section 26a. Likewise, the exposed portions 21a and 28a of the 55 sheet 2 in the flap section 25 are heat-sealed to the underlying exposed portions 21a and 28a of the sheet 2 in the bag bottom section 26a as well as to the underlying area 29a of the sheet 2 in the apexof the flap section 2411. Furthermore, by reason of the notch I8 in the liner sheet 3, the inner or outer layers or thicknesses of the sheet 2 at the apex of the flap 25a will be heat-sealed together thereby preventing all possibility of leakage or sifting of the bag contents outwardly through the bottom structure of the bag and providing a bottom structure for the bag that is completely air-tight. After the flap sections 24a and 25a have been heat-sealed together and to the respectively y ng areas of the portions 21a and 28a of the sheet 2 in the intermediate bag bottom section 26a as described, the tab 5 may be secured over and upon the folded flap sections 24a and 25a in the conventional manner, for example, by means of any suitable adhesive. In

lieu of the procedure just described, it will be obvious, of course, that the tab may be provided with a coating of thermoplastic adhesive and secured in place by the application of-heat independently of or at the same time that the flap sections 24a and 25a of the bottom structure are secured in folded relation upon the intermediate bag bottom section 260, as hereinbefore described.

From the foregoing description it will be apparent that the present invention provides bag constructions of the character described having bottoms of the self-opening automatic type or satchel type which are completely heat-sealed. The invention also provides a bag having reentrant bellows-folded side walls which is provided with a completely heat-sealed self-opening or automatic bottom that is entirely proof against the leakage or sifting of any contents outwardly through the bottom and is completely tight against the in-leakage of air. The invention further provides a bag of the flat type having a satchel bottom which is completely heat-sealed and entirely proof against leakage and sifting of the contents of the bag therethrough as well as completely air-tight. In addition, bags made according to the present invention are of comparatively simplified and inexpensive construc tion and wholly practical and eflicient in use.

While certain embodiments of the invention have been illustrated and described herein it is not intended to limit the invention to such disclosures and changes and modifications may be made therein and thereto within the scope of the claims.

I claim:

1. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away, an intermediate sheet of flexible heat-sealable material interiorly of said outer sheet and covering the cut-away areas thereof, a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet, and a closure at the bottom of the bag comprising sections of the tubular body folded inwardly from opposite sides thereof and providing a bag bottom section and endwise flap sections, one of said flap sections being folded upon said bottom section and heat-sealed thereto, and the other of said flap sections being folded upon and heat-sealed to said bag bottom section and said one flap section, the cut-away bottom edge portions of said outer sheet exposing areas of the heat-sealable intermediate sheet centrally through said bag bottom and flap sections and providing direct contact between heat-scalable surfaces of the folded over flap sections and ba bottom section.

2. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away, an intermediate sheet of flexible heat-sealable material interiorly of said outer sheet and covering the cut-away areas thereof, a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet and having in its bottom edge a recess disposed centrally with respect to one face of the bag body, and a closure at the bottom of the bag comprising sections of the bag body folded inwardly from opposite sides thereof and providing a bag bottom section and endwise flap sections, one of said flap sections being folded upon said bottom section and heatsealed thereto, and the other of said flap sections being folded upon and heat-sealed to said bag bottom section and said one flap section, the cutaway bottom edge portions of said outer sheet exposing areas of the heat-scalable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heatsealable surfaces of the folded over flap sections and bag bottom section, and said recess in the liner sheet eliminating said liner at the extremity of said other flap section and providing direct contact between inner and outer layers of said intermediate heat-scalable sheet at the extremity of said other flap section.

, the bottom end of one face of the bag, an intermediate sheet of flexible heat-scalable material interiorly of said outer sheet and covering the tab and cut-away areas thereof, a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet, and a closure at the bottom of the bag comprising sections of the bag body folded inwardly from opposite sides thereof and providing a bag bottom section and endwise flap sections, one of said flap sections being folded upon said bottom section and heat-sealed thereto, and the other of said flap sections including Jsaid tab portion of the outer sheet and being folded upon and heatsealed to said bag bottom section and said one flap section, the cut-away portions of the bottom edge of said outer sheet exposing areas of the heat-sealable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heat-scalable surfaces of the folded over flap sections and bag bottom section, and the tab portion of said outer sheet being secured in exteriorly overlying relation to said folded over flap sections. v

4. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away to provide a tab portion centrally with respect to the bottom end of one face of the bag, an intermediate sheet of flexible heat-sealable material interiorly of said outer sheet and covering the tab and cut-away areas thereof, a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet and having in its bottom edge a recess disposed centrally with'respect to the edge ofsaid tab portion, and a closure at the bottom of the bag comprising sections of the bag body folded inwardly from opposite sides thereof and providing a bag bottom section and endwise flap sections, one of said flap sections being folded upon said bottom section and heat-sealed thereto, and the other of said flap sections including said tab portion of the outer sheet and being folded upon and heatsealed to said bag bottom section and said one flap section, the cut-away bottom edge portions of the said outer sheet exposing areas of the heat-sealable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heat-scalable surfaces of the folded over flap'sections and bag bottom section, said recess in the liner sheet eliminating said liner at the extremity of said other flap section and providing direct contactbetween inner and outer layers of said intermediate heat-seal able sheet at the extremity of said other flap section, and the tab portion of said outer sheet being secured in exteriorly overlying relationto said folded over flap sections.

5. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away; an intermediate sheet of flexible heat-sealable material interiorly of said outer sheet and covering the cut-away areas thereof; a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet; seams extendouter sheet exposing areas of the heat-scalable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heat-sealable surfaces of the folded over flap sections and bag bottom section.

6. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away; an intermediate sheet of flexible heat-scalable material interiorly of said outer sheet and covering the cut-away areas thereof; a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet; seams extending longitudinally in one body face of the bag respectively comprising overlapped side edge portions of said outer, intermediate and liner sheets; and a closure. at the bottom of the bag comprising sections of the bag body folded inwardly from opposite sides thereof; creases extending transversely of the bag body through said infolded sections in predetermined spaced parallel rela-.

tion with respect to each other and the bottom end of said body defining in said infolded sections a bag bottom section and endwise flap sections, one of said flap sections being-folded upon said bag bottom section and heat-sealed thereto, and the other of said flap sections being folded upon and heat-sealed to said bag bottom section and said one flap section, the cut-away bottom edge portions of said outer sheet exposing areas of the heat-scalable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heat-sealable surfaces of the folded over flap section and bag bottom section.

7. A bag of the character described including a tubular body comprisingian outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away; an

intermediate sheet of flexible heat-scalable material interiorly of said outer sheet and covering the cut-away areas thereof; a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet and having in its wardly from opposite sides'flat upon one face thereof and providing a bag bottom section and endwise flap sections, one of said flap sections being folded upon said has bottom section and heat-sealed thereto, and the other of said flap sections being folded upon and heat-sealed to said bag bottom section and said one flap section, the cut-away bottom edge portions of the said outer sheet exposing areas of the heat-scalable intermediate sheet centrally in said bag bottom and flap sections providing direct contact between heat-sealable surfaces of the folded over flap sections and bag bottom section, and said recess in the liner sheet eliminating said liner at the extremity of said other flap section and providing direct contact between inner and outer layers of said intermediate heat-scalable sheet at the extremity of said other flap section.

8. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away;

7 bottom edge a recess disposed centrally with an intermediate sheet of flexible heat-sealable material interiorly of said outer sheet and covering the cut-away'areas thereof; a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet and having in its bottom edge a cut-away recess disposed centrally with respect to one body face of the bag; seams extending longitudinally in one body face of the bag respectivelycomprising overlapped side edge Portions of said outer, intermediate and liner sheets; a-closure at the bottom of the bag comprising sections of the bag body folded inwardly from opposite sides thereof; creases extending transversely of the bag body through said infolded sections in predetermined spaced parallel relation with respect to each other and the bottom end of said body defining in said infolded sections a bag bottom section and endwise flap sections, one of said flap sections being folded upon said Bag bottom section and heat-sealed thereto, and the other of said flap sections being folded upon and heat-sealed to said bag bottom section and said one flap' section, the cut-away portions of the bottom edge of said outer sheet exposing areas of the heat-scalable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heat-scalable surfaces of the folded over flap sections and bag bottom section, and said recess in the liner sheet eliminating said liner at the extremity of said other flapsection and providing direct contact between inner and outer layers of said intermediate heatscalable sheet at the extremity of said other flap section.

9. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predeter-' mined portions of its bottom edge cut away and providing a tab portion centrally with respect to the bottom end of one face of the bag; an intermediate sheet of flexible heat-scalable material interiorly of said outer sheet and covering the tab and cut-away areas thereof, a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet; seams extending longitudinally in onebody face of the bag respectively comprising overlapped side edge portions of said outer, intermediate and liner sheets; and a closure at the bottom of the bag comprising sections of the bag body folded inwardly from opposite sides thereof and providing a bag bottom section and endwise flap sections, one of said flap sections being folded upon said bottom section and heat-sealed thereto, and the other of of said outer sheet exposing areas of the heat-' sealable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heat-sealable surfaces of the folded over flap sections and bag bottom section, and said tab portion of the outer sheet being secured in exteriorly overlying relation to said folded over flap sections.

10. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away to provide a tab portion centrally with respect to the bottom end of one face of the bag; an intermediate sheet of flexible heat-scalable material interiorly of said. outer sheet and covering the tab and cut-away areas thereof; a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet; seams extending longitudinally in one body face of the 7 ba respectively comprising overlapped side edge portions of said outer, intermediate and liner sheets; a closure at the bottom. of the bag comprising sections of the bag body folded inwardly from opposite sides thereof; creases extending transversely of the bag body through said infolded sections in predetermined spaced parallel relation with respect to each other and the bottom end of said body deflning in said infolded sections a bag bottom section and endwise flap sections, one of said flap sections being'foldedupon said bottom section and heat-sealed thereto, and the other of said flap sections including said tab portion of the outer sheet and being folded upon and heat-sealed to said bag bottom section and said one flap section, the cut-away portions of the bottom edge of said outer sheet exposing areas of the heat-scalable intermediate sheet centrally in said bag bottom and flap sec tions and providing direct contact between heatsealable surfaces of the folded over flap sections and bag bottom section, and said tab portion of the outer sheet being secured in exteriorly overlying relation to said folded over flap sections.

11. A bag of the. character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away to provide a tab portion centrally with respect to the bottom end of one face of the bag; an intermediate sheet of flexible heat-sealable materialinteriorly of said outer sheet and covering the tab and cut-away areas thereof; a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet and having in its bottom edge a recess disposed centrally with respect to the edge of said tab portion; seams extending longitudinally in one face of the bag re spectively comprising overlapped side edge portions of said outer, intermediate and liner sheets; and a closure at the bottom of the bag comprising sections of the bag body folded inwardly from opposite sides thereof and providing a bag bottom section and endwise flap sections, one of said flap sections being folded upon said bottom section and heat-sealed' thereto, and the other of said flap sections including said tab portion of the outer sheet and being folded upon and heat-sealed to said bag bottom section and said one flap section, the cut-away bottom edge portions of said outer sheet exposing areas of the heat-sealable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heat-sealable surfaces of the folded over flap sections and bag bottom section, said recess in the liner sheet eliminating said liner at the extremity of said other flap section and providing direct contact between inner and outer layers of said intermediate heat-scalable sheet at the extremity of said other flap section, said tab portion of the outer sheet being secured in exteriorly overlying relation to said folded over flap sections.

12. A bag of the character described including a tubular body comprising an outer sheet of flexible non-heat reactive material having predetermined portions of its bottom edge cut away to provide a tab portion centrally with respect to the bottom end of one face of the bag; an intermediate sheet of flexible heat-scalable material interiorly of said outer sheet and covering the tab and cut-away areas thereof, a liner sheet of flexible non-heat reactive material disposed interiorly of said intermediate sheet and having in its bottom edge a recess disposed centrally with respect to the edge of said tab portion; seams extending longitudinally in one body face of the bag respectively comprising overlapped side edge portions of said outer, intermediate and liner sheets; a closure at the bottom of the bag comprising sections of the bag body folded inwardly from opposite sides flat upon one face thereof, creases extending transversely of the bag body through said infolded sections in predetermined spaced parallel relation with respect to each other and the bottom end of said body defining in said infolded sections a bag bottom section and endwise flap sections, one of said flap sections being folded upon said bag bottom section and heat-sealed thereto, and the other of said flap sections including said tab portion of the outer sheet and being folded upon and heat-sealed to said bag bottom section and said one flap section, the cut-away bottom edge portions of said outer sheet exposing areas of the heat-sealable intermediate sheet centrally in said bag bottom and flap sections and providing direct contact between heat-sealable surfaces of the folded over flap sections and bag bottom section, said recess in the liner sheet eliminating said liner at the extremity of said other flap section and providing direct contact between inner and outer layers of said intermediate heat-scalable sheet at the extremity of said other flap section, and said tab portion of the outer sheet being secured in exteriorly overlying relation to said folded over flap sections.

HANS VOLKSDORF. 

